Can topspin change into backspin mid rally

Aaron Lin Asked 9 years ago

me and my mate are both fairly beginner level and we were having a discussion about top and backspin.

Lets say that my friend serves backspin, I push the ball back and he returns with a forehand topspin, now the point has went from backspin into topspin.

what my mate said is that after the rally becomes topspin it will always remain topspin for the rest of the point, and if I try to make a topspin ball into backspin the ball will just go up high/off the table  is he correct? 

Is there a way to change topspin into backspin? If I try would it just cause the ball to fly up high?

Thanks